Houston Fertility Journal

Male infertility plays a role in at least 40% of infertility cases. The good news is that male infertility is often easier and less expensive to diagnose, since many causes can be uncovered with a simple semen analysis. The bad news is that male infertility is not always as simple as it seems.

Low sperm count is just one potential cause of male infertility. In many cases, there are several factors. It's also possible that both you and your partner have fertility issues. This means that both partners need to be tested, even if tests on the man reveal a fertility barrier.

Here's what you need to know about your sperm and your fertility.

Male Infertility: All About the Sperm?

Ultimately, male fertility really is all about sperm. To get your partner pregnant, you must produce enough sperm to make it to the egg, have sperm that can efficiently swim, and have a sufficiently high number of healthy sperm. This doesn't mean that a semen analysis can tell you everything you need to know about sperm health.

Internal problems can interfere with your body's ability to ejaculate or your ability to sustain an erection, for example. And even if your reproductive endocrinologist identifies a problem with your sperm or semen, you'll still have to determine the underlying cause. Hormonal imbalances, structural anomalies, medications, undiagnosed chronic illnesses, and a range of other conditions can impede sperm health. If your semen analysis doesn't provide clear answers, it may be just the beginning of male infertility testing.

Sperm Health: More Than Just Numbers

If you have a low sperm count -- defined as 15 million or fewer sperm per milliliter of semen -- your odds of getting your partner pregnant diminish. When you have fewer sperm, the odds of a healthy sperm traveling to the egg when you ejaculate are lower, though it's still technically possible to get your partner pregnant. Optimizing your partner's fertility, taking steps to ensure sperm reach the egg, and using special sperm-friendly lubricants may help.

Other sperm factors may also play a role. When combined with low sperm count, these issues can further reduce, or even eliminate, the chances of a successful pregnancy.

Sperm motility: This is a measure of how well your sperm can travel. The lower your motility, the less the chances are of reaching the egg. Low motility combined with low sperm count can prove especially problematic for fertility.

Sperm morphology: Morphology is a measure of sperm health. In every drop of sperm, some sperm will be damaged or incomplete. When a large number of your sperm are damaged, the odds of a genetic defect increase, and the potential for a pregnancy decreases.

Getting Sperm to the Egg: Not as Easy as it Seems

Even if your sperm are perfectly healthy, you will not be able to get your partner pregnant if sperm cannot travel to the egg through semen.

Some common barriers include:

Ejaculation and erectile dysfunction: If you cannot sustain an erection or ejaculate, you won't be able to fertilize an egg, even if your semen and sperm are perfectly healthy. Erectile and ejaculatory dysfunction occur for reasons ranging from psychological to structural. If you routinely have sexual difficulties, or if you have never been able to ejaculate into your partner, tell your doctor. Without this information, your doctor will not be able to accurately diagnose you.

Sperm-free semen: A number of issues can result in semen that is free of sperm. Your doctor will check you for structural defects, as well as hormonal imbalances. A key question will be whether your body produces, or is capable of producing, sperm.

Timing issues: It doesn't matter how healthy your sperm is. If you and your partner do not correctly time intercourse, a pregnancy won't be possible. A woman's most fertile time is immediately before ovulation, not after, since the egg survives an average of just 12 hours. Sperm can live up to a week in a woman's reproductive tract, so consider having sex every other day leading up to ovulation, as well as the day after ovulation.

Genetic defects: If your sperm carries genetic defects, it may not fertilize the egg even if it reaches its destination. Alternatively, genetic defects can interfere with the egg's ability to implant in the uterus, or lead to an early miscarriage. In some cases, these miscarriages are so early that the woman doesn't even know she is pregnant.

If you cannot ejaculate or sustain an erection, you might not be able to easily submit to a semen analysis. Your doctor can discuss options for extracting semen. Some men cannot masturbate in a doctor's office, so if this happens to you, you may be able to collect semen in a condom after having sex with your partner.

Semen Quality

Pregnancy requires a complex interplay between the woman's reproductive tract and the man's semen. Issues with semen quality can make it difficult for otherwise healthy sperm to travel within a woman's reproductive tract. In some cases, a woman's body may even attack semen as if it is a foreign pathogen.

A semen analysis can tell you a lot about the quality of your semen. That includes:

Semen volume: More semen typically means more sperm.

Semen pH: A pH that is too low or too high may damage sperm, or cause the woman's body to attack the sperm.

White blood cell count: There should not be white blood cells in semen; if there are, it suggests an infection.

Liquefaction time: This is a measure of how quickly semen becomes liquid.

Fructose level: Fructose (sugar) is a source of energy for sperm.

If a semen analysis is inconclusive, or if your doctor suspects that there is a problem with the interaction between your body and your partner's, your doctor might order additional tests.

Occasionally, doctors even have couples engage in intercourse immediately before an appointment so that the doctor can observe how the sperm behaves within the woman's reproductive tract.